Multi-activity offshore exploration and/or development drilling method and apparatus

• US 6,068,069 A
• Filed: 04/14/1999
• Issued: 05/30/2000
• Est. Priority Date: 05/03/1996
• Status: Expired due to Term

• Current Assignee: Transocean Offshore Deepwater Drilling Incorporated (Transocean Limited)
• Original Assignee: Transocean Offshore (U.K.), Inc.
• Inventors: Scott, Robert J., Herrmann, Robert P., Ray, Donald R.
• Primary Examiner(s): NEUDER, WILLIAM P
• Application Number:
  US09/291,483
• Time in Patent Office: 412 Days
• Field of Search: 175/52, 175/57, 175/85, 175/161, 175/167, 175/170, 166/77.5
• US Class Current: 175/5
• CPC Class Codes: B63B 2003/147 Moon-pools, e.g. for offshore drilling vessels
• CPC Class Codes: B63B 35/4413 Floating drilling platforms, e.g. carrying water-oil separating devices
• CPC Class Codes: E21B 15/02 specially adapted for underwater drilling E21B15/04 takes precedence
• CPC Class Codes: E21B 19/002 specially adapted for underwater drilling E21B19/09, E21B19/143 take precedence
• CPC Class Codes: E21B 7/12 Underwater drilling using heave compensators E21B19/09

Abstract

A multi-activity drillship, or the like, method and apparatus having a single derrick and multiple tubular activity stations within the derrick wherein primary drilling activity may be conducted from the derrick and simultaneously auxiliary drilling activity may be conducted from the same derrick to reduce the length of the primary drilling activity critical path.

Claims

1. A drillship having a bow, a stern and an intermediate moon pool between the bow and stern and being fitted to conduct offshore drilling operations through the moon pool and into the bed of a body of water, said drillship including:

a unitary derrick having four sides joined at their edges and having a central opening within the derrick, said unitary derrick being positioned upon the drillship and extending above the moon pool for simultaneously supporting drilling operations for a wellhole and operations auxiliary to drilling operations for the wellhole through the moon pool;

a first means within and connected to said unitary derrick for advancing tubular members through the moon pool, to the seabed and into the bed of the body of water;

first means, within and connected to said unitary derrick, for handling tubular members as said tubular members are advanced through the moon pool by said first means for advancing;

a second means within and connected to said unitary derrick for advancing tubular members through the moon pool to the seabed and into the bed of the body of water; and

second means, within and connected to said unitary derrick, for handling tubular members as said tubular members are advanced through the moon pool by said second means for advancing for conducting operations for the wellhole extending to the seabed auxiliary to said drilling operations for the wellhole, wherein said drilling activity can be conducted from said unitary derrick by said first or second means for advancing and said first or second means for handling tubular members and auxiliary drilling activity can be simultaneously conducted from said unitary derrick by the other of said first or second means for advancing and the other of said first or second means for handling tubular members.

2. A drillship as defined in claim 1 wherein said first and second means for advancing tubular members comprise:

a first and second top drive assembly respectively.

3. A drillship as defined in claim 1 wherein said first and second means for advancing tubular members comprise:

a first and second rotary table positioned within said unitary derrick.

4. A drillship as defined in claim 3 wherein:

said first rotary table and said second rotary table being mutually spaced along a center line of the drillship and within the periphery of said unitary derrick.

5. A drillship as defined in claim 1 and further including:

a first driller'"'"'s console operable to control said first means for advancing tubular members; and

a second driller'"'"'s console substantially similar to said first driller'"'"'s console and being operable to independently control said second means for advancing tubular members.

6. A drillship as defined in claim 1 and further including:

a first tubular setback envelope positioned adjacent to said first means for advancing tubular members; and

a second tubular setback envelope positioned adjacent to said second means for advancing tubular members.

7. A drillship as defined in claim 6 and further including:

a third tubular setback envelope positioned between said first tubular setback envelope and said second tubular setback envelope.

8. A drillship as defined in claim 6 and further including:

a tubular handling system for transferring tubular members between said first tubular setback envelope and said second tubular setback envelope and said first means for advancing tubular members and said second means for advancing tubular members.

9. A method for conducting offshore drilling operations into the bed of a body of water, for a single well, from a drilling deck operable to be positioned above the surface of the body of water, said method being conducted, at least partially, from a first station for advancing tubular members and, at least partially, from a second station for advancing tubular members, the method including the steps of:

(a) drilling a well bore comprising at least a portion of a wellhole into the bed of the body of water from the first or second station for advancing tubular members;

(b) running at least one casing from the first or second station for advancing tubular members into the at least a portion of the wellhole;

(c) simultaneously during at least a portion of the time period utilized for performing steps (a) and (b), running a blowout preventer and riser into the body of water from the other of said first or second station for advancing tubular members to a position in proximity to the at least a portion of the wellhole in the seabed, wherein the events of step (c) are performed independently of and during at least a portion of the same time period as the events of steps (a) and (b) to reduce the overall time necessary to perform steps (a) through (c) for conducting offshore drilling operations from the drilling deck on a single well being drilled into the bed of the body of water;

(d) laterally repositioning the drilling deck until the other of said first or second station for advancing tubular members and the blowout preventer and riser are positioned over the well bore comprising at least a portion of a wellhole; and

(e) connecting the blowout preventer and the riser extending from the other of said first or second tubular station onto the at least one casing in the well bore comprising at least a portion of a wellhole at a location in proximity to the seabed.

10. A method for conducting offshore drilling operations into the bed of a body of water, for a single well, from a drilling deck operable to be positioned above the surface of the body of water as defined in claim 9 and further comprising the steps of:

(f) making-up extended lengths of tubular members at the first or second station for advancing tubular members;

(g) transferring the extended lengths of tubular members made up at the first or second station for advancing tubular members to the other of said first or second station for advancing tubular members; and

(h) using the extended lengths of tubular members, made up at the first or second station for advancing tubular members, conducting drilling operations coaxially through the riser and into the single wellhole from the other of said first or second station for advancing tubular members.

11. A method for conducting offshore drilling operations into the bed of a body of water, for a single well, from a drilling deck operable to be positioned above the surface of the body of water as defined in claim 9, said drilling deck being mounted upon a floating vessel, wherein said step (d) of laterally repositioning the drilling deck until the other of said first or second station for advancing tubular members is positioned over the well bore comprising at least a portion of a wellhole comprises the step of:

laterally repositioning the vessel supporting the drilling deck, said vessel floating generally upon the surface of the body of water.

12. A method for conducting offshore drilling operations into the bed of a body of water, for a single well, from a drilling deck operable to be positioned above the surface of the body of water, said method being conducted, at least partially, from a first station for advancing tubular members and at least partially from a second station for advancing tubular members, the method including the steps of:

(a) drilling a well bore comprising a first portion of a wellhole into the bed of the body of water from one of said first or second stations for advancing tubular members;

(b) running a first casing from one of said first or second stations for advancing tubular members into the first portion of the wellhole;

(c) drilling at least a second portion of the wellhole having a diameter smaller than the diameter of the first portion of the wellhole into the bed of the body of water coaxially through the first casing from one of said first or second stations for advancing tubular members to a depth greater than the depth of the first portion of the wellhole;

(d) running a second, smaller diameter, casing from one of said first or second stations for advancing tubular members coaxially through the first casing and into the second, smaller diameter, portion of the wellhole drilled in step (c); and

(e) simultaneously during at least a portion of the time period utilized for performing steps (a) through (d), making-up and running a blowout preventer and riser into the body of water from one of said first or second stations for advancing tubular members not then occupied performing at least one of one of steps (a) through (d) to a position in proximity to the wellhole in the seabed, wherein the events of step (e) are performed independently of and during at least a portion of the same time period as the events of steps (a) through (d) to reduce the overall time necessary to perform steps (a) through (e) for conducting offshore drilling operations from the drilling deck, on a single well, being drilled into the bed of the body of water;

(f) following completion of the events of steps (a) through (d) laterally repositioning the drilling deck until the blowout preventer and riser is positioned over the well bore of the wellhole; and

(g) connecting the blowout preventer and the riser onto the second casing in the single wellhole approximately at the seabed of the body of water.

13. A method for conducting offshore drilling operations into the bed of a body of water, for a single well, from a drilling deck operable to be positioned above the surface of the body of water, as defined in claim 12, and further comprising the steps of:

during at least a portion of the period of step (e) using said one of said first or second stations for advancing tubular members to make-up a bottom hole assembly for use in conducting drilling operations through the riser.

14. A method for conducting offshore drilling operations into the bed of a body of water, for a single well, from a drilling deck operable to be positioned above the surface of the body of water as defined in claim 12 and further comprising the steps of:

(h) making up extended lengths of tubular conduits at one of said first or second stations; and

(i) using the extended lengths of tubular conduits at the one of said first or second stations and using the extended lengths of tubular members for conducting drilling operations coaxially through the riser and into the single wellhole.

15. A method for conducting offshore drilling operations into the bed of a body of water, for a single well, from a drilling deck operable to be positioned above the surface of the body of water, said method being conducted, at least partially, from a first station for advancing tubular members and at least partially from a second station for advancing tubular members, the method including the steps of:

(a) making up and running to the seabed a first casing from the first station for advancing tubular members and making up a first bottom hole assembly, running a drillstring to the seabed and drilling a first section of a wellhole from the second stations for advancing tubular members, at least a portion of the activity of each station for advancing tubular members being performed simultaneously;

(b) re-aligning the first station for advancing tubular members so that it is positioned above the wellhole drilled by the second station for advancing tubular members in step (a);

(c) landing the first casing on the wellhole, cementing and testing and, with the second station for advancing tubular members, making up a second bottom hole assembly and running said second bottom hole assembly to the seabed;

(d) re-aligning the second station for advancing tubular members so that it is positioned above the wellhole;

(e) making up and running to the seabed a second casing from the first station for advancing tubular members and drilling a second section of a wellhole from the second station for advancing tubular members, at least a portion of the activity of each station advancing tubular members being performed simultaneously;

(f) re-aligning the first station for advancing tubular members so that it is positioned above the wellhole;

(g) landing the second casing on the wellhole, cementing and testing and, with the second station for advancing tubular members, making up a third bottom hole assembly and running said third bottom hole assembly to the seabed;

(h) re-aligning the second station for advancing tubular members so that it is positioned above the wellhole;

(i) rigging up and running a blowout preventer and a marine riser to the seabed from the first station for advancing tubular members and drilling a third section of a wellhole, retrieving the drillstring, making up and running to the seabed a third casing from the second station for advancing tubular members, landing, cementing and testing said third casing;

(j) re-aligning the first station for advancing tubular members so that it is positioned above the wellhole;

(k) landing and latching the blowout preventer to the wellhead from said first station for advancing tubular members and making up and standing back a bottom hole assembly for the next wellhole section from the second station for advancing tubular members; and

(l) picking up the bottom hole assembly for the next wellhole section, running to the seabed, and drilling the next wellhole section from the first station and making up and setting back stands of casing for the next wellhole section from the second station for advancing tubular members, at least a portion of the activity being performed simultaneously.

16. The method for conducting offshore drilling operations as defined in claim 15:

wherein the step of re-aligning the first or second station for advancing tubular members includes laterally repositioning the drilling deck.

17. A multi-activity drilling assembly operable to be supported from a position above the surface of a body of water for conducting drilling operations to the seabed and into the bed of the body of water, said multi-activity drilling assembly including:

a drilling superstructure operable to be mounted upon a drilling deck for simultaneously supporting drilling operations for a well and operations auxiliary to drilling operations for the well;

a first tubular advancing station connected to said drilling superstructure for advancing tubular members to the seabed and into the bed of body of water;

a second tubular advancing station connected to said drilling superstructure for advancing tubular members simultaneously with said first tubular advancing station to the seabed and into the body of water to the seabed; and

an assembly positioned adjacent to said first and second tubular advancing stations operable to transfer tubular assemblies between said first tubular advancing station and said second tubular advancing station to facilitate simultaneous drilling operations auxiliary to said drilling operations, wherein drilling activity can be conducted for the well from said drilling superstructure by said first or second tubular advancing stations and auxiliary drilling activity can be simultaneously conducted for the well from said drilling superstructure by the other of said first or second tubular advancing stations.

18. A multi-activity drilling assembly as defined in claim 17 and further including:

a first tubular setback station positioned adjacent to said first tubular advancing station; and

a second tubular setback stationed positioned adjacent to said second tubular advancing station.

19. A multi-activity drilling assembly as defined in claim 17 wherein said first and second tubular advancing stations comprise:

a first and second top drive assembly connected to said drilling superstructure.

20. A multi-activity drilling assembly as defined in claim 17 wherein said first and second tubular advancing stations comprise:

a first and second rotary table positioned adjacent to said drilling superstructure for assisting in performing drilling operations and for simultaneously assisting in performing operations auxiliary to drilling operations through the drilling deck.

21. A multi-activity drilling assembly as defined in claim 17 wherein said first tubular advancing station and said second tubular advancing station include:

a first drawworks for hoisting tubular members; and

a second drawworks for hoisting tubular members respectively.

22. A method for conducting offshore drilling operations with a multi-activity drilling assembly operable to be mounted upon a drilling deck positioned above the surface of a body of water and having a first tubular station and a second tubular station, the method including the steps of:

advancing tubular members from the first tubular station and into the bed of a body of water to the seabed for conducting drilling operations for a well;

advancing tubular members from the second tubular station and into the bed of a body of water to the seabed for conducting activity auxiliary to drilling activity for the well; and

transferring tubular members between the first tubular station and the second tubular station wherein primary drilling activity can be conducted by advancing tubular members from the first or second tubular station and auxiliary drilling activity can be conducted simultaneously for the well by advancing tubular members to the seabed from the other of the first or second tubular station.

23. A method for conducting offshore drilling operations as defined in claim 22 wherein said step of advancing the tubular members from the first tubular station functions includes:

rotating the tubular members with a first top drive supported from an upright superstructure.

24. A method for conducting offshore drilling operations as defined in claim 23 wherein said step of advancing the tubular members from the second tubular stations includes:

rotating the tubular members with a second top drive supported from an upright superstructure.

25. A method for conducting offshore drilling operations as defined in claim 22 wherein said step of advancing tubular members from the first second tubular stations includes:

rotating tubular members at said first tubular station with a rotary table; and

rotating tubular members at said second tubular station with a second rotary table.

26. A method for conducting drilling operations as defined in claim 22 wherein said steps of advancing first and second tubular members includes:

hoisting tubular members from a first tubular station; and

hoisting tubular members from a second tubular station respectively.